Characteristics of a 20-year-old evergreen broad-leaved forest restocked by natural regeneration after clearcut-burning

1
College of Resources and Environment Science, Central South University of Forestry and Technology, Changsha, 410004, Hunan, China 2
Tropical Biosphere Research Center, University of the Ryukyus, Taketomo-Cho, Okinawa, 907-1541, Japan 3
Faculty of Agriculture, University of the Ryukyus, Okinawa, 903-0213, Japan 4
The United Graduate School of Agriculture Science of Kagoshima University, Japan

Received 4 Dcember 2007; accepted 5 March 2008; published online 4 July 2008

Abstract - To elucidate the application of natural regeneration to the restocking of
evergreen broad-leaved forests in the subtropics, the characteristics of a
20-year-old evergreen broad-leaved forest restocked by natural regeneration
after clearcut-burning were studied in Okinawa, Japan. Within a 0.87 ha
clearcut area with four 10 m 10 m sampling plots, two burned and
two unburned ones, the tree composition, tree species diversity and
vegetation changes were investigated. The results showed that the species diversity, basal area and density of
woody stems 1.0 m in height differed significantly among
phanerophyte types, while they were not significantly different between the
burned and unburned treatments. A vegetation census also revealed no obvious
differences between the treatments. The primary dominant species, Castanopsis sieboldii, continued to dominate the
secondary forest with a broad height distribution. The structural complexity and high tree species diversity of the
regenerating forest after clearcut-burning provides no evidence of
degeneration. We can predict that the regeneration forest may gradually
develop into stands similar to pre-clearcut primary forest, and that natural
regeneration may restore the high tree species diversity of the evergreen
broad-leaved forests in Okinawa.